Reciprocating tape



Feb. 19, 1957 G. w. TEBBS RECIPROCATING TAPE:

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United States Patent RECIPROCATING TAPE.

George William Tebbs, London, England, assignor to Headley Townsend Backhouse, Nassau, Bahamas, British West Indies Application October 4, 1954, Serial No. 460,126

Claims priority, application Great Britain October 8, 1953 Claims. (Cl. 271f3) The invention relates to conveyors for sheet material, especially sheets of paper, card 'or the like, of the kind (hereinafter referred to as the kind described) comprising a horizontal or sloping support board or table and one or more conveyor tapes above the board or table, the tape or each tape moving parallel to the upper surface of the board or table and making engagement with a sheet thereon to move the sheet over the board or table. It is an object of the present invention -to provide an improved form ofsuch a conveyor which will positively feed the sheet in two or more steps, such a conveyor being particularly useful for example in feeding sheets over vthe bed or table lof a printing machine which operates to make impressions on the sheets in the interval between the successive steps. A further object is to provide such a conveyor in which the sheets are stepped between the successive steps with a degree of positional accuracy suitable for many purposes.

The expression tape as used herein is not restricted to flexible elements of thin flat section but includes elongated exib'le elements of other sections such as round section wire which may be multi-stranded.

The invention provides a conveyor of the kind described in which the tape is given a reciprocatory movement and has for movement with it, two or more abutments (e. g. forwardly directed hooks) which during successive strokes in the forwarding direction engage in succession behind the rear edge of a sheet and push the sheet step by step over the board or table and then return idly into position ready for engagement during a following stroke in the forward-ing direction with the rear edge of another sheet.

ln a preferred form of the invention there are two tapes, or two laps of a single tape, which are both parallel to the board or table as aforesaid and move in opposite directions and the abutments aforesaid are distributed between the two tapes or laps and operate in out of phase relation. in practice such an arrangement will usually be duplicated for engagement with the sheet adjacent the side edges thereof.

The tape or tapes may be attached to a `driving pulley or drum to which oscillatory motion is given and means may be provided for automatically braking the pulley or drum at one -or each end of its movements whereby the extent of the .movement of the pulley or drum and of the tape or tapes in at least one direction may be accurately determined for the purpose of Idetermining the position at which the sheets are stopped.

In a preferred form there are two tapes attached at their ends in laterally disposed relation to two drums or pulleys, and the two tapes extend in opposite directions from the drums or pulleys and in laterally disposed parallel relation `over the table yor board.

The abutments may be so disposed on the tape or tapes in relation to the length `of the stroke and the size of the sheets that each abutment moves the sheet by any amount up to the full length of the stroke, as is required to bring any part of the sheet into an exact position on the table,

at the end of the stroke. It is preferred that the abutments are adjustable in position along the tape or tapes, whereby the proportion of the stroke of each abutment which is employed to push the sheets may be varied.

The invention is particularly suited for application to conveyors for conveying sheets over the table of an addressing or like machine which effects a printing `operation on the sheets while lying on the table, e. g. 'by pressing a portion of the sheet downwardly on to a printing plate lying in or slightly below the plane of the table. Such machines usually have a presser head which rises and falls in an arcuate path to effect the printing operations and in a practical form of this application of the invention the movements of the head are employed to effect the reciprocatory movements of the conveyor tape or tapes.

The conveyor according to the invention may be used, for example lto feed sheets to an addressing machine and a specific form -of the invention suited for this application Will now be described by way of example and with reference to the accompanying drawings in which:

Figure l is a side view of the conveyor;

Figure 2 is a plan view of the conveyor, and y Figures 3-5 are diagrams illustrating one Way in which the conveyor may be operated.

The conveyor forming the subject -of this example is in front of and overlaps a first conveyor which is a tape conveyor of Well known form and is used to deliver sheets from a sheet separator to the conveyor of the present example. The present conveyor extends lover the addressing mach-ine table 111 and operates, between printing operations, to feed the sheets beneath the printing head indicated at 112. At the rear of the conveyor there is'a shaft 113 which has `driving means to `effect oscillation thereof as later described. The shaft carries two pulleys 114 of substantial diameters and adjustable along the length thereof to lie just within the width of sheets of `different sizes. At the front of the conveyor there is a fixed 'bar 115 carrying two lbrackets 116 supporting for rotation two pulleys 11S, the brackets being adjustable along the bars to maintain alignment between the pulleys 118 and the pulleys 114. Each of the pulleys 114, 118 has two shallow flat based circumferential grooves and attached to each of the pulleys 114 there are two lengths `of flexible steel tapes 119, 121i which lie in the two grooves respectively. The tapes are secured to the pulley at one point on the circumference thereof, in laterally displaced relation (i. e. in the two grooves) and extend around the pulley in opposite directions. The tape 119 leaves the pulley at the bottom and passes over, and close to, the table 111 to and beneath the corresponding pulley 11S to which it is attached. The other tape 120 passes downwardly from the pulley 114 and under a jockey pulley 122 (supported from a fixed bar 123) which holds this tape also close to the table and the tape then passes along side the tape 119 over the table 111, under a seco-nd jockey pulley 125 (supported on the |bracket 116) and over the top of the front pulley 118 to which it is attached. Each tape carries .several downwardly and forwarding directed hooks 126 which rub on the surface of the table 111 (or may extend into shallow channels formed between parallel strips fixed on the table). The hooks are clamped to the tapes and adjustable along their lengthsl to effect forwarding of the sheetsv to variable positions of registration and, if desired, to forward each sheet to successive registered positions. If desired the hooks may be resilient so as to apply light spring pressure onto the table. The backs yof the hooks are chamfered so that they may ride over the front edge of a sheet during their return movements.

The driving means for the shaft 113 will now be described. Fixed to the shaft near one end thereof there is a small gear wheel 128 with Which meshes a larger wheel 130 supported for rotation on a stub shaft 132 fixed to a side frame member. This larger wheel has a radially directed fork 134 on the opposite side of Vthe stub shaft to the smaller wheel. Pivoted on the bar 123 there is a bell-crank lever 136 of which one arm extends rearwardly towards the shaft 113 and has a pin 133 which, over part of the movement ofthe lever, is .rc- `ceived within the fork 134.. The other arm of the lever is connected by links 14d and 141 to the presser head 112 so that the fore and aft component of the up and down movements of the head reciprocates the links 149 and 141 and oscillates the lever 136. When the head is raised the pin 138 is at the top of its movement and slightly above a line joining the pivotal axes of the le ver 136 and the wheel 130. Downward movement of the head 112 rocks the bell-crank 136 to move the pin 138 downwardly and so to rotate the fork 134 and to cause the gear 13G to drive the pulley shaft 113 about three-quarters of a turn in one direction. Before the head reaches the lower limit of its travel (i. e. before the printing operation) the fork and pin have reached positions (shown in chain lines) in which the pin moves radially to the larger gear-wheel and out of the mouth of -the fork so that the drive to the pulley shaft is discontinued. Upward movement of the presser head causes reverse movements, including reverse movement of the pulley shaft and the tapes driven thereby. Consequently the tapes 119, 12) of each pair are given reciprocatory movements in opposite directions but are stationary when printing is effected.

Secured to the pulley shaft 113 there is a brake disc 142 of rubber or like resilient material and extending around a part of the disc there is an arcuate brake shoe 144 which hangs from a pivot 145 above the disc. The dise and shoe lie behind the fork and the fork has two abutments-constituted by rearwardly directed adjustable screws 146, 147 of which one is above and the other below the axis of oscillation of the fork. When the fork is at the upper limit of its movement the `upper abutment 146 contacts the brake shoe and presses it into engagement with the disc. During the movement of the hook the shoe is released but when the hook reaches the lower limit of its travel the lower abutment 147 engages the shoe and presses it onto the disc. The shaft is therefore braked at each end of its movement and over-run of the tapes is largely prevented.

In the operation of the machine a sheet fed onto the table from the separator by the first conveyor is engaged at its rear edge by each of the two first hooks on the tapes at each side of the machine and is advanced during the forward movement of the tapes into printing position on the machine table. This movement occurs during the first part of the downward movement of the presser head. The hooks are so positioned on the tapes that the length of stroke remaining after they engage the sheet is appropriate to move the sheet to the desired printing position= the first part of the stroke being idle unless the whole of the stroke is needed. The sheet remains stationary during the last part of the downward movement and the first part of the upward movement of the head during which printing is eliectetL-and may J then be picked up either by hooks on the second tapes and advanced during the upward movement of the head or by different hooks on the first tapes during the next downward movement of the head, depending upon the adjustment of the hooks. The sheet may be advanced only so far as is desired for a further printing operation or it may be removed entirely to a receiving hopper or the like. If only one impression is required on the sheet it will usually bc convenient to adjust the hooks so that hooks on the second tapes are positioned to engage the sheet and to remove it completely from the printing position. 1f, on the other hand, the sheet is to be advanced only a short distance for a second impression, then the next hook to be used may be on either tape as most convenient.

Figures 3-5 are diagrams illustrating one way in which the machine may operate to advance a fresh sheet for each printing operation. A sheet B fed onto the table by the first conveyor 150 is engaged by hooks 12651 on the tapes 119 as shown in Figure 3. The tapes 119 then move to the left toY advance the sheet beneath the presser head 112 (i. e. to the position shown in Figure 4) the movement occurring `during the first part of the descent of the head. After the printing operation the tapes 119 move to the right and the hooks 126s move idly over a fresh sheet A which has been advanced by the conveyor 150. At the same time the tapes i2() move to the left and hoo :s 1261) thereon advance the sheet B away from the printing position as shown in Figure 5. The .preceding sheet is also simultaneously advanced towards a receiving station `by hooks 126C on the tapes 120.

For the purpose of reducing any tendency of the sheets to over-run or to return with the hooks, there may be provided friction means (e. g. resilient pressure strips seating on the sheets) which tend to resist movement of the sheets.

Other means for driving the pulley may be used. For example there may be a gear quadrant engaging the gear on the shaft and oscillated by a link from the presser head. The link may operate through a lost motion device to move the quadrant in one direction and the return movement may be effected by a spring. There may also be means whereby the brake aforesaid is applied at the end of a variable part of the return move ment (during which a sheet is forwarded) thereby to discontinue the movement when the sheet has been fed an appropriate amount.

I claim:

1. `A conveyor for sheets comprising a surface for supporting the sheets, two parallel side-by-side iiexible elongated members each reciprocable lengthwise parallel to and above the support surface, means for giving such reciprocatory movement to said members in out of phase relation, and at least two abutments distributed between the two members and carried thereby, said abutments being operable to engage in succession behind the rear edge of a sheet during movement of the members in one direction (the forwarding direction) and to push the sheet step by step over the surface and to return idly during movement of the members in the opposite direction into position ready for engagement during a following movement in the forwarding direction with the rear edge of another sheet.

2. A conveyor as claimed in claim l in which the two elongated members consist of flexible tapes which are attached at their ends to spaced pulleys and the means for giving reciprocatory movements to the members operate by oscillating the pulleys.

3. A conveyor as claimed in claim 2 in which the two tapes are provided by two laps of a single tape.

4. A conveyor as claimed in claim l in which the abutments are in the form of forwardly directed hooks.

5. A conveyor as claimed in claim l which comprises a rotatable member to which at least one of the Iiexible members is fixed, means for giving oscillatory motion to the rotatable member and means for automatically braking the rotatable member at, atleast, one end of its oscillatory movement whereby the limit of the movement of the flexible member in at least one direction is accurately determined.

6. A conveyor as claimed in claim 1 in which the elon gated members consist of two iiexible tapes, in which there are two pulleys spaced apart in the direction of the length of the tapes and to which the two tapes are attached at their ends in laterally disposed relation, the two tapes extending partly around the pulleys in opposite directions and travelling between the pulleys in laterally disposed parallel relation over the support surface.

7. A conveyor as claimed in claim l in which the n be varied.

8. A `conveyor as claimed in claim 1 in combination with an addressing machine of the kind having a printing head to which up and down movements are given and which effects a printing operation at the end of its downward movement in which combination the means for giving reciprocatory movements to the members are arranged for operation by the movements of the presser head of the addressing machine.

9. The combinationfof a conveyor and an addressing machine as claimed in claim 8 in which said means include a lost motion device whereby the portion of the movement of the head during which the printing s effected by the head is ineffective to move the members.

10. The combination of a conveyor and an addressing machine as claimed in claim 9 in which said means and said 10st motion device comprises a lever, a link for connecting the lever to the head whereby the movements of the head rock the lever, an oscillatable fork, an abutment on the lever which enters the fork to eiect rotation thereof during the rst part of the stroke of the lever, leaves the fork during the last part and returns into the fork during the return stroke whereby the end portion of the stroke of the lever-which corresponds to the end of the downward movement of the head at which printing is effectedis ineffective to rotate the fork and means for translating oscillation of the fork into movements of the tape or tapes.

References Cited in the le of this patent UNITED STATES PATENTS 2,200,409 Backhouse May 14, 1940 2,375,989 Hale May 15, 1945 

